This invention relates to an ultrasonic channel diffuser, particularly a radial one, and to a method of manufacture of such ultrasonic diffuser, particularly a radial one, applicable in the construction of the flow compressors of all kinds, particularly ultrasonic ones.
Those skilled in art know channel diffusers produced by making suitable channels of a circular cross section in a cylindrical ring (U.S. Pat. No. 3,333,762) or channels of a rectangular cross section (U.S. Pat. No. 3,765,792). Sometimes, for practical reasons, channels are made in two half-rings sandwiched together in the parting plane perpendicular to the axis of the ring (U.S. Pat. No 4,012,166). In all the afore mentioned cases inter-channel walls are permanently connected to the side walls of the ring and the leading edges of the inter-channel walls are the result of penetration of surfaces which form the channels. In the case of a channel having a circular cross section the leading edges of inter-channel walls have an elliptical shape and in the case of a channel with a rectangular cross section the leading edges are straight lines. In diffusers with the elliptical leading edges, the inter-channel wall on the side of the compressor impeller exists in the initial part at the walls only thus forming, so to speak, partial blades, which combine with each other only at some distance from the compressor impeller, thus forming separate channels. In consequence, an extensive zone of pseudovanes is produced, wherein the diffuser acts on the stream of the medium in the vicinity of side walls only, whereas the central portion of the stream is braked with considerable losses in a blade-less diffuser, produced and developed especially in the radial direction with an existing relatively large zone of an ultrasonic flow. In the diffusers with recti-linear leading edges of the walls, at the inlet of the channels there is produced a strong perpendicular shock wave and some zone of ultrasonic flow. The process of passage of the medium through one shock wave isn't efficient enough and the existence of a zone of an ultrasonic flow causes in effect additional losses. The design of diffuser with additional vanes with rectilinear leading edges introduced in the inlet portion of the diffuser known from the U.S. Pat. No. 3,765,792 decreases in effect the area of an ultrasonic flow, but doesn't eliminate the process of braking of flow in one perpendicular shock wave.